The nazi zombie levels are a bonus co-op mode where endless waves of the undead attack you and up to 3 other players in this fun survival mode.

Levels

Nacht Der Untoten - Night of the Undead

Verrück - Zombie Asylum

Shi No Numa - Zombie Swamp

Der Riese - Zombie Factory

Secrets

Hidden Easter Eggs in the zombie maps.

Tactics

Survival Guide - Tips and tactics to help last longer!